This invention relates to a tamper-proof sealing device that is particularly adapted for use in the housings of postage meters.
In many countries, requirements are provided which regulate the use of postage meters and their security against unauthorized use or vandalism. There have been several systems devised or suggested in this regard, but none have experienced wide-spread commercial use because of their complexity, cost or ineffectiveness. Many of these prior art devices are cumbersome, heavy mechanisms that are not only costly to manufacture, but are difficult to install and use. Additionally, other security devices are difficult to repair and/or to easily find replacement parts for. In addition, when it is desirable to convert a normally secure postage meter into a more tamper-resistant closure, an inexpensive and relatively simple device is needed. While simplicity and convenience are desirable in a security system, the primary concern should be the effectiveness of the device.
In some countries outside of the United States, the government through its responsible agencies requires tamper-proof access mechanisms that prevent unauthorized access to the interior of the postage meters. There is therefore a need for a relatively inexpensive yet effective means for indicating unauthorized use of postage meters and the like.
Prior art construction of security seals or other types of security devices generally consists of a number of components that are expensive to fabricate. Several of such seals or devices require a tool in order that they can be installed or closed. Other prior art constructions heretofore known do not totally eliminate the possibility of undesired tampering or manipulation. A construction described in the prior art comprises a sheet metal strip drawn through the opening or openings of an article which is to be sealed. After the sheet metal strip is flexed over upon itself, it can be riveted at both of its ends by tongs or pliers. The rivet location is subsequently covered with a plastic cap. With this construction seal, there is the drawback that riveting of the sheet metal strip is not undertaken in a completely faultless manner. Tampering or manipulations for the purpose of providing a false seal or giving the appearance that the article has in fact been sealed is possible.
According to another state of the art construction of a security seal, both ends of a flexible strip have associated therewith rather bulky closure elements. Thus, this construction of seal cannot be employed in those instances in which the opening or openings of the article to be sealed is small, especially in conjunction with slot-shaped openings or apertures.
In addition, with this prior art construction of seal, the catch elements of the locking elements (even when the seal was closed) are freely accessible so that it is easy to provide a false or improper seal of the article. Other known seals have been employed on security containers and other repositories of valuable materials as a safeguard against tampering or unauthorized opening, but they are generally difficult to install or expensive for continuing use. While these seals do provide assurance that unauthorized openings have not occurred, such seals can generally be circumvented. This is done by anyone having access to a supply of seals by simply replacing a broken seal with a new one. Counterfeiting seals also would not be difficult for someone willing to go to the considerable time and expense involved.
In some containers, seals having a very high degree of assurance are required to indicate if unauthorized access has occurred. Some known seals to be used on postage meters, for example, do have a high degree of integrity but at a relatively high cost in both time and money. When using presently available devices to assure that a seal has not been replaced, a plurality of intricate and expensive means have been attempted.
There have been many sealing devices utilizing a frangible or destructible membrane and a device such as these has been described in Dutch patent application No. 7,412,131 or U.S. Pat. Nos. 2,142,048, 3,983,645 and 3,924,800. Devices like these are used for dispatching documents in transportation bags. One such device takes the form of a flat envelope having along one of the edges a zip fastener which, in closed position, is sealed by means of a rupturable or frangible sealing member. In order to be able to establish afterwards that the transportation bag has been opened by a person unauthorized to do so, one must be able to ascertain if the seal is original or a replacement. With such a sealing device, it would be possible to reapply the sealing member quickly and without use of aids, thus giving the impression that the sealing member was never broken. In the sealing device disclosed in the above-noted Dutch patent, the elastic means which are to be deformed are formed by resilient lips projecting from the shaft portion of the sealing member. In the head of the sealing member there is formed a slit wherein a special tool can be engaged for twisting said sealing member in order to break same. It is obvious, however, that in addition to being complex, a design such as this leads to a relatively high cost for the sealing members, especially upon continued use. There is a need to provide a simple and inexpensive sealing device of the type that will be described herein in which no specific or expensive tool is required to break the sealing member thereof.
The present invention provides a destructible or frangible paper seal that is intimately connected to the locking mechanism in such a manner that the opening of the lock will cause destruction of this paper seal or membrane.